A sensor assembly comprises for example a sensor measuring or detecting a physical parameter and providing an analog sensor signal to an amplifier. Usually the sensor assembly has a dynamic range within which linear amplification is guaranteed. Analog sensor signals having a value extending this range may be distorted by saturation of the amplifier.
For measuring parameters within a greater range of signal amplitudes the sensitivity of the sensor or the gain of the amplifier has to be reduced leading to values of reduced signal to noise ratio.
International Patent Publication No. WO 2009/143434 A2 describes a microphone assembly is known comprising two microphones having different dynamic ranges. From the signals amplified by the two microphones an external selector selects and switches to that microphone being best matched to the incoming signal level, i.e., to the incoming sound pressure level.
One disadvantage of this assembly is that the second microphone requires double circuitry and thus, double effort.
U.S. Pat. No. 6,628,795 B1 describes a hearing aid comprising an automatic gain control varying a gain of the hearing aid in response to a detected sound level such that the hearing aid may work within a desired range below a clipping or pain threshold. In a multichannel hearing aid, independent gain control units are used for each channel. Problems arise when trying to actively cancel noise with an ANC (=active noise canceling) method using the multiple signals of the multichannel hearing aid.